Rod bending apparatus

ABSTRACT

A guideway formed in a frame retains a series of rollers which form respective central pivot points for a plurality of interlinked arms. Each arm includes an offset point which becomes pivotally linked with an adjacent arm so that rotational motion of the rollers causes simultaneous scissoring action of the linkage arms. A straight rod is secured to the interconnected linking arms and during the scissoring action the rod becomes bent into a sawtooth pattern.

United States Patent Hart [ 51 3,657,914 1 Apr. 25, 1972 [54] ROD BENDING APPARATUS [72] Inventor: James A. Hart, 2210 Dewitt Street, lrving, Tex. 75060 [22] Filed: Dec. 8, 1969 [21] App1.No.: 882,848

[52] [1.8. CI. ..72/383, 72/D1G. 16, 140/105 [51] Int. Cl ..'.B2ld 7/024 [58] Field ofSearch ..140/105;72/383,384,385,

72/386, DIG. l6

[56] References Cited UNITED STATES PATENTS 2,661,787 12/1953 Eidal ..72/383 3,486,536 12/1969 Frantz ..140/1l2 2,702,576 2/1955 Eidal ..72/383 2,815,062 12/1957 Cook et al. 140/105 Primary Examiner-Lowell A. Larson Attorney-Clarence A. O'Brien and Harvey B. Jacobson [5 7] ABSTRACT A guideway formed in a frame retains a series of rollers which form respective central pivot points for a plurality of interlinked arms. Each arm includes an offset point which becomes pivotally linked with an adjacent arm so that rotational motion of the rollers causes simultaneous scissoring action of the linkage arms. A straight rod is secured to the interconnected link ing arms and during the scissoring action the rod becomes bent into a sawtooth pattern.

6 Claims, 9 Drawing Figures PATENTEDAPR 25 I972 sum 1 BF 3 &ue

James A Harl M lllllll NM vm 1...

1 an L PATENTEDAPR 25 I972 SHEET 3 BF 3 i -aanmdw- James A. Hart INVENTOR,

ROD BENDING APPARATUS The present invention relates to a machine for bending an elongated rod. 7

The present invention is a machine adapted to bend a straight elongated rod into asawtooth pattern. Such bent rods are conventionally utilized as webs for structural shapes and for forming reinforcing rods for concrete constructions. In the past, machines have been fabricated for the purpose of bending straight elongated rods into a zigzag pattern and one common machine of this type includes a lazy tong assembly having means thereon for initially gripping a straight rod. Under the effect of compressive forces, the assembly becomes shortened and forces the conforming bending of the rod into a zigzag pattern. However, this type of prior art machine does not continually grip those portions of the rod that become apexes. As a result, the bending of the rod in the critical apex regions is not completely controlled and a completely regular or symmetrical series of sawtooth shapes is difficultto achieve, particularly with heavier rods.

The present invention is directed to a rod bending machine utilizing interconnected linkages which undergo scissoring action. However, unlike the prior art, the present invention uses a simple series of interconnected scissor arms instead of the more complex lazyv tong members. The scissor arms of the present device continually grip spaced points along the length of a straight rod during a bending operation so that complete control at the critical apex regions of the bending rod is efgregating displacement of rollers and 24, the obtuse angle between arms 18 and 22 is lessened as the arms rotate about pivot point 26 until a final acute angle is maintained. The rotational motion of the arms 18 and 22 can therefore be likened fected. As a result, the present invention offers the metal fabricator a less expensive mechanism which operates more reliably on a larger range of rod sizes than the prior art.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIG. 1 is a top plan view illustrating the relationship between the linkage arms of the present invention.

FIG. 2 is a partial sectional view taken along a plane passing through section line 2--2 of FIG. 1. It should be noted that the linkage arms are not taken in section so that theyappear in side elevation. y

FIG. 3 is a transverse sectional view taken along a plane passing through section line 3-3 of FIG. 2.

FIG. 4 is a partial sectional view taken along a plane passing through section line 4-4 of FIG. 2.

FIG. 5 is a top plan view of the apparatus illustrated in FIG.

I after attainment of a full bending position.

FIG. 6 is a partial transverse view taken along a plane passing through section line 66 of FIG. 1.

FIG. 7 is a sectional view taken along a plane passing through section line 7-7 of FIG. 6.

FIG. 8 is an exploded view showing the components of spacer members inserted in a guideway between linkage arm pivot rollers which assure uniform spacing between zigzag portions of a finished bent rod.

FIG. 9 is a schematic illustration of a fully bent rod as posi tioned with respect to the pivot points of the rod bending linkage arms.

Referring to the figures and more particularly FIG. 1, the present rod bending apparatus is generally indicated by reference numeral 10 and is seen to include elongated parallel spaced guideway tracks 12 and 14 defining a guideway having uniform width. The guideway tracks are mounted to a frame 16 which supports the rod bending assembly to be discussed.

The bending assembly includes a plurality of interconnected linkage arms pairs that are serially connected along the guideway. The first arm of each pair is designated by reference numeral 18 which is mounted on a roller 20 disposed in the guideway and fixedly connected to the arm 18 at the median point therealong. The second arm of each pair is indicated by 22 and will be seen to form an initial obtuse angle with the preceding arm 18. The latter mentioned arm 22 is likewise mounted at a median point thereof to a second roller 24 posito scissoring action. A substantially maximum point of linkage arm rotation is pictured in FIG. 5 wherein the obtuse angle between arms 18 and 22 will be seen to have been decreased to an acute angle. As will be noted in FIG. 1, the complete rod bending apparatus includes the series of just explained linkage arm pairs that form a linkage train. Due to the fact that each of the successively positioned linkage arms is supported by its own roller, and further due to the fact that adjacent linkage arms are interconnected by a common pivot point, the entire linkage train undergoes simultaneous scissoring action in response to compressive sliding displacement 'of the linkage rollers. A slidably mounted bracket 28 is positioned on each of the arms 18 and serves to mount a right angle bracket 30 thereon which is positioned adjacent the pivot pin 26 also passing through the bracket. As a result, a portion of an elongated straight rod 32 can be positioned between confronting surfaces of the angle bracket 30 and the pivot pin 26. Inasmuch as each linkage arm 18 includes a bracket 28 with the rod engaging members thereon, the entire length of the rod is engaged at regularly spaced intervals therealong. i

The basic operation of the present invention includes means for simultaneously rotating the rollers of the linkage arms toward one another causing the linkage arms to undergo scissoring action and assume the substantially final disposition shown in FIG. 5. During the scissoringaction, the pivot pins 26 form critical supports for forming the apexes of the finally bent rod. More particularly, the pivot pin 26 serves as a fulcrum around which the associated rod portion is bent to form an apex. This action is diagrammatically illustrated in FIG. 9 wherein the finished bent rod will be seen to resemble a symmetrical sawtooth or'zigzag pattern which is the desired end product of the bending operation. The bent rod is then removed from the machine and means are provided for dis placing the rollers away from each other resulting in the assumption of the linkage arms in the: initial position seen in FIG. 1.

Considering FIGS. 2 and 3, the particular structure of the rod bending mechanism is seen to include a plurality of equidistantly spaced transverse plates 34 mounted to vertically oriented framework members 36. Transversely aligned and spaced fasteners 38 pass through the plates 34 and serve to support a longitudinally extending base bearing plate 40. The web portions of two oppositely directed channel members 42 bound the longitudinal marginal edges of plate 40 while the guideway rails 12 and 14 rest upon the upper flanges of the channels 42. As indicated in FIG. 3, the longitudinally extending space between confronting edges of the rails 12 and 14 defines a guideway 46. The guideway 46 intimately abuts alternatingly positioned shafts 48 and 49 (FIG. 2) that serve as pivot points for the linkage arms 22 and 18. The connection points between shafts 48 and 49 and their respective linkage arms are effected at points above the guideway rails 12 and 14 to provide clearance and the lower ends of the shafts are axially keyed to identically formed rollers 50 and 52 associated with shafts 48 and 49, respectively. In order to have the linkage arms 18 and 22 positioned in the intimate overlying relation, the roller shafts are alternatively staggered in the longitudinal dimension. However, as will be noted, all shafts indicated by 48 are of the same length and all shafts indicated by 49 are of the same length. An anchor roller 56 is positioned outside the left end of the guideway 46 and is fixedly mounted to the frame by means of a shaft 49 received in a journal 58 secured to the guideway tracks 12 and 14. A modification to the mounting of the right end roller 60 includes the use of an extended shaft 62 disposed in perpendicular skew relation to the right end linkage arm 22 for purposes of driving the linkage train as hereinafter explained. A washer element 64 is mounted to shaft 62 in overlying contacting juxtaposition with the guideway 46 and engages an adjacent guideway spacer to limit inward travel of roller 60.

The primary means for driving the linkage arm train to a full rod bending position is achieved by a conventional powered winch 66 which controls the feed of a cable 68. As will be seen in FIG. 2, the cable 68 sequentially entrains the rollers 56, 50, 52, and 54. The free end of cable 68 passes through a diametrically formed bore in the right end roller 60 for eventual securement to a mechanical stop 70 on the free end of the cable. Thus, at the initiation of a rod bending operation, cable 68 is wound onto winch 68 thereby causing simultaneous rotation of the aforementioned rollers. The rollers 50, 52 and 54 will undergo rotational sliding motion toward the anchor roller 56 as the cable 68 becomes wound on the winch spool. Due to the way cable 68 is received through the right end roller 60, this roller only slides along the guideway 46 but does not rotate as do the intermediately positioned rollers. As a result of the rotational sliding motion of the rollers disposed in guideway 46, torque is exerted upon associatively connected linkage arms thereby causing these arms to assume the substantially final position shown in FIG. 5. As a result, the rod being carried on the linkage arms assumes the symmetrical sawtooth or zigzag configuration shown in FIG. 9. After removal of the bent wire from the machine, it is necessary to return the mechanism to the original position as shown in FIG. I. To achieve this, a second powered winch 73' has a cable portion 72, independent from cable 68, wrapped around the right end roller 60 in a sense opposite the direction of winding cable 68 on the other rollers. Thus, upon winding of winch 73, the rollers rotatingly slide outwardly to their initial position.

The right end roller 60 is designed in aiding to bend rod 32 into its final shape. To see how roller 60 achieves this end, reference is made to FIG. 1 wherein shaft 62 associated with roller 60 is seen to protrude outwardly from guideway 46. As cable 68, lying in vertical underlying relation to the illustrated rod 32, is pulled in the direction of the winch 66 (FIG. 2), shaft 62 serves as a cam engaging a confronting edge of linkage member 22. The shaft 62 will continue to travel in the left direction under the pulling influence of cable 68 and will follow the right linkage arm 22 as the entire linkage arm train is undergoing scissor action by virtue of the rotation of the other rollers. However, as will be explained hereinafter, mechanical stops are positioned between the rollers so that they may come into preselected proximity to one another without actually making contact. In order to aid the scissor action, shaft 62 continues to exert its influence upon the right end linkage arm 22 thereby, in effect, exerting supplementary lever forces that are transmitted throughout the linkage train. Accordingly, due to a combination of roller rotation and the camming effect of shaft 62 on the right linkage arm 22', the linkage train can assume the full bending position shown in FIG. 5.

As will be noted in FIG. 1, adjustment means are provided on each linkage arm 18 which allows the machine user to choose the amplitude of the finally bent rod that is illustrated -in FIG. 9. Considering the left end linkage arm 18, a plate member 74 defines the central body of the linkage arm 18. A left transverse bracket 76 is positioned in longitudinal spaced relation to an intermediately positioned bracket 78 of similar design. Actually, these brackets are journals for a threaded bar 80 which is disposed between the brackets 76 and 78. The left end of the threaded bar 80 includes a crank handle 82 which adjusts the position of a slidably mounted bracket 84 carried by the threaded bar 80. In the case of the left end linkage arm 18, two confrontingly positioned angle brackets 86 clamp the left end of rod 32 therebetween so that the rod does not fall away from the bending apparatus during bending. However, as will be noted in the figure, all other slidably mounted brackets similar to 84 only include a single angle bracket disposed in confronting relation to the pivot pin 26 interconnecting adjacent linkage arms.

A second adjusting mechanism is positioned on each linkage arm 18 and includes a fixed journal bracket 88 disposed in parallel spaced relation to the aforementioned bracket 78, the pivot point 20 of the linkage arm 18 separates the brackets 78 and 88. The right end of the linkage arm mounts a fourth journal bracket 90 so that a second threaded shaft 92 can be journaled therebetween. A crank handle 94 is attached to the right end of the threaded shaft for facilitating screwing rotation of the shaft. The aforementioned sliding bracket 28 'is threadingly carried by the threaded shaft 92 and is identical to the sliding brackets on each of the remaining linkage arms 18. As previously explained, the pivot pin 26 is received in the bracket 28 and is pivotally joined with an underlying adjustable bracket connected to associated linkage arm 22 and discussed hereinafter. Thus, by varying the position of the pivotally connected sliding brackets, the obtuse angle between adjacent linkage arms 18 and 22 can be varied to effect a variable amplitude of the finally bent rod. Of course, in order to operate the present machine effectively, all threaded shafts must be adjusted so that a symmetrical linkage train is formed. Otherwise, binding and jamming of the mechanism would result.

Considering FIG. 6, the specific construction of a slidably displaceable bracket 28 and its relation to the engaged linkage arms are clearly shown. The bracket 28 is seen to include overlying plates 97 and 100 that are rigidly connected to perpendicularly disposed spacer plates 102 and 104. The central body portion 74 of the linkage arm 18 passes in the space created by the overlying plates 97, 100 and perpendicularly connected spacer plates 102 and 104. The plate 97 includes an aperture therein for receiving a hollow sleeve 96. An elongated bolt passes through the sleeve 96 and serves as the pivotal axis of pivotally connected linkage arms 18 and 22. It will be noted that the lower end of sleeve 96 rests upon the underlying plate 100 of the slidable bracket 28. The angle bracket 30 includes perpendicular flanges one of which is fastened to plate 97 by a fastener 98. The other flange is disposed in confronting parallel relation with bolt 26 thereby permitting the insertion of rod 32 therebetween. The space between the confronting flange and pivotal sleeve should be designed to intimately engage and frictionally retain the rod therebetween.

Once the disposition of the slidable bracket 28 is selected, setscrews 106 threadingly mounted in plate 104 are adjusted to bear against the central body portion 74 of linkage arm 18. Due to the fixed connection between plate 104 and the overlying sliding bracket plates 97 and 100 (FIG. 6), tightening of setscrews 106 fixes the relation between the sliding bracket 28 and the linkage arm 18.

By studying FIGS. 6 and 7, the exact disposition of threaded shaft 80 relative to the bracket plates 97 and 100 will be appreciated. Specifically, a journal 108 welded to plates 97 and 100 threadingly supports the shaft 80.

A similar configuration of horizontally disposed plates 110 and 114 bound the upper and lower surfaces of the linkage arm 22 and form an adjustable bracket 109. The pivot pin 26 passes through plates 110 and 114 while a nut 116 secures the pin in position. A washer 112 is disposed between the lower plate 100 associated with linkage arm 18 and the upper plate 110 associated with linkage arm 22. Thus, relative rotation between linkage arms 18 and 22 around the axis defined by bolt 26, can be realized. Between the plates I10 .and 114 are transversely disposed spacer plates 118 and 120 serving the same function as the aforementioned spacer plates 102 and 104. Spacer plate 118 mounts two aligned setscrews 122 which are loosened when the setscrews 106 are loosened thereby permitting mutual adjustment of the slidable brackets associated with linkage arms 18 and 22. Thus, when the amplitude of the bending apparatus is to be changed, the setscrews 106 and 122 associated with linkage arms 18 and 22, respectively, are loosened until the threaded shafts are adjusted to achieve a selected angular relation between the linkage arms 18 and 22. Then, the setscrews are tightened so that the angular relationship between the linkage arms can be maintained.

As previously mentioned, means are provided in the guideway 46 for insuring that uniform spacing between the rollers can be realized thereby resulting in preselected uniform pitch between successive cycles in a bent rod pattern. Referring to FIGS. 4 and 8, the spacer means are indicated by reference numeral 124 and will be seen to include a first rectangular plate 126 and a second parallel spaced overlying plate 128 positioned in sandwiching overlapping relation with the guideway. An intermediate block 130 is suitably connected to the internal surface of plate 128 and rides in the guideway. Apertures 134 and 136 are formed through the overlying plates 128 and 126, respectively, while a suitable bolt 132 passes therethrough for securement by a nut member 138 at the opposite end thereof. The spacer block 130 has a thickness that is slightly less than the thickness of the guideway tracks 12 and 14 so that by loosening bolt 132, the spacer means 124 can be slidingly positioned in the guideway. After proper positioning, the fastener 132 is tightened whereby plates 126 and 128 clamp the spacer means 124 in the guideway. Thus, as will be appreciated by viewing FIG. 4, the spacer means 124 provides a minimum spacing between adjacently displaced rollers at the attainment of maximum bending. The spacer means 124 can be interchanged with similar assemblies of different dimensions when the pitch between successive cycles of a bent rod is to be changed. Presently, only four standard pitch dimensions are employed in bent rod webs used in structural members. Thus, with four such sets of differently sized spacer means, the machine user can fabricate bent rods having any pitch presently utilized. Of course, any other pitch within the operating range of the machine can be employed by merely utilizing a suitably dimensioned spacer means. Also, instead of the fixed dimensioned spacer means 124, suitably adjustable spacer means may be employed so that substitution of differently sized spacer means would be unnecessary when converting the machine from one pitch to another.

In summary, the present invention is directed to a machine that can be extended in sections to an infinite length to take the longest rod that can normally be hauled in freight and bend this rod into a symmetrical sawtooth or accordion pattern. This machine can be adjustably set to repeat a predetermined pattern having a constant amplitude and pitch in a finished bent rod with either tapered or straight, regular or irregular cyclical patterns.

It should be noted that although the right hand roller 60 has been shown to secure the free end of the driving cable 68 thereat, in applications utilizing very heavy rods this cable could be wrapped around the right end roller 60 and directed back to the left end either directly or through the serially disposed adjacent rollers thereby rendering an increase in the torque applied to the rod.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

lclaim:

l. A rod bending machine comprising a frame, a longitudinally elongated guideway formed in said frame, a plurality of longitudinally aligned mounting rollers rotatably and slidably positioned in the guideway for rotational and longitudinal movement therealong, a plurality of serially and pivotally interconnected links supported by respective mounting rollers for movement in response to a combined rotation and sliding of said rollers, means attached to the links for retaining a rod against the links throughout the movement thereof, and means for rotatably and slidably driving the mounting rollers longitudinally along said guideway to a congregated position causing the links to ex erience scissoring action, whereby the linkretarned rod is bent into a predetermined pattern, said means for driving said mounting rollers comprising an elongated cable, said cable extending along the length of said guideway and being wound in opposite directions about adjacent rollers in a manner whereby a pull on one end of said cable will effect an opposite rotational movement of adjacent rollers and a corresponding complementary pivoting of the pivotally interconnected links for a movement of the pivotally engaged portions of the links laterally of the longitudinal guideway.

2. The apparatus of claim 1 wherein each pair of adjacent links is pivotally interconnected by pivot means located laterally of the links, and bracket means securing the links to the corresponding pivot means.

3. The apparatus of claim 2 wherein said means for retaining a rod comprises a pair of clamp means mounted on alternate links, each clamp means engaging the opposite sides of the rod for a gripped retention thereof on the link.

4. The apparatus of claim 3 wherein each clamp means is mounted on one of the aforementioned brackets, each bracket means being longitudinally adjustable along the corresponding link, each bracket mounted clamp means being adjustable along with the corresponding bracket.

5. The apparatus of claim 4 including bracket adjusting means, said bracket adjusting means comprising a threaded shaft rotatably mounted on a corresponding link and rotatably engaged with a corresponding link mounted bracket whereby rotation of the threaded shaft effects a. longitudinal adjustment of the bracket along the link, and means for selectively locking each bracket in its longitudinally adjusted position.

6. A rod bending machine comprising a frame, a longitudinally elongated guideway formed in :said frame, a plurality of longitudinally aligned mounting rollers rotatably and slidably positioned in the guideway for rotational and longitudinal movement therealong, a plurality of serially and pivotally interconnected links supported by respective mounting rollers for movement in response to a combined rotation and sliding of said rollers, means attached to the links for retaining a rod against the links throughout the movement thereof, and means rotatably and slidably driving the mounting rollers longitudinally along said guideway to a congregated position causing the links to experience scissoring action, whereby the linkretained rod is bent into a predetermined pattern, said means for retaining a rod comprising a pair of clamp means mounted on alternate links, each clamp means engaging the opposite sides of the rod for a gripped retention thereof on the link, each pair of adjacent links being pivotally interconnected by pivot means located laterally of the links, and bracket means securing the links to the corresponding pivot means, each clamp means being mounted on one of the aforementioned brackets, each bracket means being longitudinally adjustable along the corresponding link, each bracket mounted clamp means being adjustable along with the corresponding bracket. 

1. A rod bending machine comprising a frame, a longitudinally elongated guideway formed in said frame, a plurality of longitudinally aligned mounting rollers rotatably and slidably positioned in the guideway for rotational and longitudinal movement therealong, a plurality of serially and pivotally interconnected links supported by respective mounting rollers for movement in response to a combined rotation and sliding of said rollers, means attached to the links for retaining a rod against the links throughout the movement thereof, and means for rotatably and slidably driving the mounting rollers longitudinally along said guideway to a congregated position causing the links to experience scissoring action, whereby the link-retained rod is bent into a predetermined pattern, said means for driving said mounting rollers comprising an elongated cable, said cable extending along the length of said guideway and being wound in opposite directions about adjacent rollers in a manner whereby a pull on one end of said cable will effect an opposite rotational movement of adjacent rollers and a corresponding complementary pivoting of the pivotally interconnected links for a movement of the pivotally engaged portions of the links laterally of the longitudinal guideway.
 2. The apparatus of claim 1 wherein each pair of adjacent links is pivotally interconnected by pivot means located laterally of the links, and bracket means securing the links to the corresponding pivot means.
 3. The apparatus of claim 2 wherein said means for retaining a rod comprises a pair of clamp means mounted on alternate links, each clamp means engaging the opposite sides of the rod for a gripped retention thereof on the link.
 4. The apparatus of claim 3 wherein each clamp means is mounted on one of the aforementioned brackets, each bracket means being longitudinally adjustable along the corresponding link, each bracket mounted clamp means being adjustable along with the corresponding bracket.
 5. The apparatus of claim 4 including bracket adjusting means, said bracket adjusting means comprising a threaded shaft rotatably mounted on a corresponding link and rotatably engaged with a corresponding link mounted bracket whereby rotation of the threaded shaft effects a longitudinal adjustment of the bracket along the link, and means for selectively locking each bracket iN its longitudinally adjusted position.
 6. A rod bending machine comprising a frame, a longitudinally elongated guideway formed in said frame, a plurality of longitudinally aligned mounting rollers rotatably and slidably positioned in the guideway for rotational and longitudinal movement therealong, a plurality of serially and pivotally interconnected links supported by respective mounting rollers for movement in response to a combined rotation and sliding of said rollers, means attached to the links for retaining a rod against the links throughout the movement thereof, and means rotatably and slidably driving the mounting rollers longitudinally along said guideway to a congregated position causing the links to experience scissoring action, whereby the link-retained rod is bent into a predetermined pattern, said means for retaining a rod comprising a pair of clamp means mounted on alternate links, each clamp means engaging the opposite sides of the rod for a gripped retention thereof on the link, each pair of adjacent links being pivotally interconnected by pivot means located laterally of the links, and bracket means securing the links to the corresponding pivot means, each clamp means being mounted on one of the aforementioned brackets, each bracket means being longitudinally adjustable along the corresponding link, each bracket mounted clamp means being adjustable along with the corresponding bracket. 